Oceaneering C-NavX1 User Manual page 105

GAGAN (GPS Aided Geo Augmented Navigation) an Indian satellite system that provides a set of corrections
f or the GPS satellites, which are valid f or the Indian region. They incorporate satellite orbit and clock corrections.
Geodetic Leveling Network is a network of vertical control or benchmarks whose heights are known as
accurately as possible, and whose horizontal position is known only approximately.
Geoid is the gravity-equipotential surf ace that best approximates mean sea level over the entire surf ace of the
earth. The surf ace of a geoid is too irregular to use f or GNSS readings, which are measured relative to an
ellipsoid. Conventionally surveyed positions ref erence a geoid. Calculating the distance between the geoid and
ellipsoid at each position and subtracting this f rom the GNSS altitude measurement can obtain more accurate
GNSS readings.
Geoidal Height is the undulation of the geoid above or below the ref erence ellipsoid.
Geographical Information System (GIS) is a computer system capable of assembling, storing, manipulating,
updating, analyzing, and displaying geographically ref erenced inf ormation, i.e. data identif ied according to their
locations. GIS technology can be used f or scientif ic investigations, resource management, and development
planning. GIS sof tware is used to display, edit, query, and analyze all the graphical objects and their associated
inf ormation.
Global Positioning System (GPS) geometrically, there can only be one point in space, which is the correct
distance f rom each of f our known points. GPS measures the distance f rom a point to at least f our satellites f rom
a constellation of 24 NAVSTAR satellites orbiting the earth at a very high altitude (approximately 20,200 km).
These distances are used to calculate the point's position.
GLONASS short f or GLObalnaya NAvigatsionnaya Sputnikovaya Sistema, is a Russian satellite -based
navigation system that works alongside GPS (Global Positioning System) to provide position inf ormation to
compatible devices. With an additional 24 satellites to utilize, GLONASS compatible receivers can acquire
satellites up to 20% f aster than devices that rely on GPS alone.
GPS Time is a measure of time. GPS time is based on UTC but does not add periodic 'leap seconds' to correct
f or changes in the earth's period of rotation. As of June 2012 GPS time is 16 seconds ahead of UTC.
Greenwich Mean Time (GMT) is the local time of the 0° meridian passing through Greenwich, England.
Handover Word is the word in the GPS message that contains time synchronization inf ormation f or the transf er
f rom the C/A-code to the P-code.
Horizontal Geodetic Network is a network f or which the horizontal, coordinate, latitude, and longitude of the
control points in the network are determined as accurately as possible, and heights are known only
approximately.
Independent Baseline those baselines that provide a unique position solution f or a given station.
Integer-cycle Ambiguity is the unknown number of whole carrier cycles between the satellite and the receiver.
IODC Issue of Data, Clock - The IODC indicates the issue number of the data set and thereby provides the user
with a convenient means of detecting any change in the correction parameters. The transmitted IODC will be
dif f erent f rom any value transmitted by the satellite during the preceding seven days.
Ionosphere is the region of the earth's atmosphere between the stratosphere and the exosphere approximately
50 to 250 miles above the earth's surf ace.
Ionospheric Refraction Delay is a delay in the propagation of the GNSS signal caused by the signal traveling
through the ionosphere.
CNAV-MAN-061
Revision B
C-NavX1 GNSS Receiver User Manual
DOC-TEM-28-NUM Rev A Uncontrolled copy when printed
C-Nav
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